832 REPORTS ON THE STATE OF SCIENCE. 



results on the depth of pelagic animals have a value of tlieir own ; but 

 our best haul, from a collector's point of view, was that of a large net, 

 mouth 1 yard in diameter, length about 12 yards, made of strong mosquito 

 cloth, 8 meshes to the inch. This net we let down on 1,200 fathoms of 

 wire, and hauled in as fast as our winch could take it. Unfortunately, 

 the wire became tied up, but the comparison of the contents of the tin 

 with the collections made by the Fowler net showed that the net itself 

 must have actually sunk to nearly 1,000 fathoms. The presence in the tin 

 of a series of prawns (one 6 inches long), a cuttle-fish, and many strong- 

 .swimniing jelly-fish, suggests that the use of this method of investigating 

 the swimming fauna (nekton) of the sea should yield valuable results. 



The Chagos Archi2)elago. 



On May 19 we anchored in Peros Bjinhos, but the weather conditions 

 caused us to make Salomon Atoll our first base. We remained there for 

 three weeks, subsequently .^pending ten days in Peros and a week each in 

 Diego and Eguiont, while Commander Boyle T. Somerville and the officers 

 of H.M.S. ' Sealark ' carried on surveying work ; we also dredged round 

 Salomon Atoll. Previously there were no bottom soundings between the 

 banks and shoals of the group, but now a large series (more than 100) 

 have been run, showing depths of 400 fathoms to 800 fathoms between 

 the individual banks ; from most of these information as to the nature 

 of the bottom has been obtained. 



Broadly speaking, the Chagos group may be said to consist of three 

 atolls to the north (Salomon, Peros Banhos, and Blenheim), the great 

 Chagos Bank in the centre (60 miles by 90 miles), and to the i;outh two 

 atolls, Diego Garcia and Egmont, besides certain submerged banks, both 

 to the north and south. Of these, H.M.S. ' Sealark ' rc-charted Salomon 

 and parts of Peros Banhos, while Cooper and I, in addition, examined the 

 southern atolls. Salomon was very carefully re-surveyed, our intention 

 being to make a comparison between its condition at the present time 

 and when Powell's chart was made in 1837. The latter chart, however, 

 jjroved to have been so carelessly drawn that aiiy close comparison is, we 

 think, useless, but the new chart should be of great value when it is 

 pcssible to re-examine the atoll at some future date. Its section lines 

 show that it rises in the last 400 fathoms by similar slopes to those of 

 Funafuti, but it is a much simpler atoll, having only one passage, and 

 more than half its reef crowned by land. Our numerous soundings and 

 dredgings on its slopes leave no room for doubt but that its present reef 

 is extending outwards on eA^ery side on its own talus ; in fact, that the 

 steep found round it (and, indeed, most atolls) is, in this instance, simply 

 the slope at which coral and other remains from the reef above come to 

 rest in the water. Its face was everywhere singularly barren ; Lithotham- 

 nton, Folylrema and, of course, reef-corals were not obtained below 

 50 fathoms. Further out, at 250 fathoms and over, the bottom was 

 smooth and barren ; the lead constantly failed to bring up any samples, 

 while the somewhat broken and dented but almost empty dredges gave 

 the idea of bare rock with a little muddy sand here and there. Indeed, 

 our evidence points to the impossibility of any upward growth being in 

 progress between the different Chagos Banks, and to the probability of 

 considerable currents being felt even at 500 fathoms. 



The reefs of the Chagos are in no way peculiar, save in their extra- 



